That was a year that was..

[Mk2 Chopper]

Would not the weight of the bumpers make a difference? 

Gareth

[Bfg]

Sunday ..drive out in the countryside

^ without leaves on the tress the country lanes were looking a bit bleak ..but today was mild and overcast ..and so for January I'm certainly not complaining about being able to drive around with the roof open 

Destination was to be Sutton Hoo, museum and Anglo-Saxon royal burial site, but I opted to carry on instead to Orford Castle (keep) which I'd visited before but not since the scaffolding had been taken down to reveal the rendering now applied to the outside of the keep, which is thought to have been applied originally but which had long since washed away. 

     

^ Viewed onto the keep's north side.  The people in the bottom right of the photo give you a scale of this castle's keep.  The new sand-coloured rendering is to keep water out and help preserve the castle's structure.  I had a good conversation with Ben, one of the castle's experts and there's apparently no academic agreement that this tower was, or was not, once white washed.  I put it to him that as an aid to shipping (navigation / positioning), and as a statement Royal supremacy and military power then the rendering of this tower would most likely have been washed brilliant white (like the white tower of London was).  Seen thus and with the flags of both king and country flying from its towers Then it must have been an easy to spot landmark ..and an awe-inspiring patriotic sight, to any ship passing along the east coast.  Ben seemed to be in agreement with these suggestions. 

Our conversation continued along the lines that the garrison assigned to man this castle was unusually small (for a castle), but its role, as built, was at a watchtower (used as such even during the 2nd WW)  ..not least against invasion from the Flemish or French.  And a lighted beacon on the top of one of its towers could be seen from Framlingham (just 10 miles away) and also Bewdsey Castle (which i understand was lost to sea erosion), a similar distance away down the coast, military support could be called upon at short notice. 

 

^ Another of the questions I came away with, from my previous visit, was why would have a keep have a kitchen or stove on each floor. The pictures here show the one up in the top of the tower, ie., on the battlements. It is a large oven. The second photo shows its insides, which is probably 4 foot across.  Why have an oven right up on the roof ? My suggestion was that a fire had to be kept alight 24/7 ..in case the tower's distress beacon needed to be lit. so if the fire was burning anyway, why not use it to bake bread ? 

There was also a chimney from the basement, next to the well. And again, just a suggestion was that this would have been for heating water used in the keep. Which sorta fits in with this particular castle being predominantly run by clerics ..who were both scholarly and supposedly more trustworthy to oversee accounts record port fees / import duties. 

We also discussed a chamber in the basement, seemingly isolated from the main basement where there's the well. In some documents it's referred to as a cell, in others it is said to be a prison.  My hypothesis was that it was as cell, which is also a term commonly used to refer to a private room in monasteries, and that it was inhabited by a cleric, but that it's role was not as prison but as a strongroom (which is in the strongest part of the castle) for import taxes paid by merchant ships using this port, and for records of accounts (tally sticks and scrolls) from the local farms.   The cell has a separate garderobe (toilet) cubical and a slotted window, neither of which would have been necessary if the space was actual a dungeon type prison. 

From what I gather, in medieval times an aristocrat or knight.. ie a high-value (ransom) prisoner would be kept in much better accommodation, lesser prisons would normally be kept in a secure room in, or near, the castle's gatehouse (where screams could not be heard by the gentile in the keep), and any other criminal would be locked in the stocks or simply be put to death.  Again Ben was kind enough to listen and be open to these / my suggestions. He went on to ask / suggest I put them to English Heritage. 

So as you might gather, interesting conversations between enthusiasts...  castle nerds ? 

 

^ Viewed onto the keep's south-west side -  in the afternoon sunshine

 

^ this erosion of the stone is in the entrance foyer, and a reminder that the building was open to the elements for hundreds of years before being re-roofed and part renovated.  It's also a great expense for English Heritage and the other trusts to maintain the building in a safe state for visitors, but at the same time not to just clad everything that was original.    ^^ a small selection of Orford museum pieces are on display, some the coins date back 1500 or more years, these (in the photo) are relative modern.   I understand that various places had their own mint. for example I was reading the other day about Bury St.Edmund's Abbey, and apparently they minted their own coins. 

^ from the keeps battlement ; Katie  in the foreground, the town of Orford, the river Ore, and then Orford-Ness (shingle spit of land) with its military testing grounds fading into the East coast / north sea horizon.

  

^ It was a good visit but soon time to go home..

As I said in my last post, the suspension does feel better balanced (the front-end's handling feels a little more settled), but I feel the ride height is still 3/4" too high for a sports-car.   I'm suffering from a twisted-wrist at the moment and so don't wish to push the car, so for now I'll leave it alone - to see how I get on with her over the next couple of months. 

That's it, and again I bid you a good evening,

Pete.

 

 

[Bfg]

19 minutes ago, Mk2 Chopper said:

Would not the weight of the bumpers make a difference? 

Gareth

yes, but I think not at all very much Gareth.

Pete

[Bfg]

1 hour ago, boxofbits said:

When TRGB say standard, do they mean poundage or height? What is the  WM factory ride height for these?

TRGB say standard and refer to normal ride height.  no poundage is stated.

Certainly Katie  appears a little high compared to what I remember of road-test photos of the TR4's and 4A's in the 1960's.  However... I was in the motor-trade / sports car design in the late 1970's early '80's and for press photos we loaded our car to make them look more sporty when no-body's weight was in the car. 

Ground clearance was stated in those tests to be 6"  ..and that is probably very close to what I now have (without driver + passenger weight). 

It does strike me though, that the radiator shield (seen under the front valance) is very apparent on Katie,  as if the body is sitting high on the chassis.  Even with bumpers on, the number plate doesn't drop below the valance enough to disguise that.  But as I cannot change the body mounting's height - then that's something we'll just have to live with.    

Pete

 

 

 

Edited January 29, 2023 by Bfg

[stuart]

14 hours ago, boxofbits said:

In my opinion Pete’s car is a little high all round, and was, I thought in previous photos prior to the suspension rebuild.

I was informed a few years ago by the TR Shop I think it was that you cannot obtain springs that will give you ‘factory standard’ ride height for these cars. I have since tried a few springs but found the ride height was too high.

When TRGB say standard, do they mean poundage or height? What is the  WM factory ride height for these?

This is my car fairly recently with a change back to factory springs. 
 

 

That looks a bit low to me at the front.

Stuart.

[stuart]

13 hours ago, Bfg said:

TRGB say standard and refer to normal ride height.  no poundage is stated.

Certainly Katie  appears a little high compared to what I remember of road-test photos of the TR4's and 4A's in the 1960's.  However... I was in the motor-trade / sports car design in the late 1970's early '80's and for press photos we loaded our car to make them look more sporty when no-body's weight was in the car. 

Ground clearance was stated in those tests to be 6"  ..and that is probably very close to what I now have (without driver + passenger weight). 

It does strike me though, that the radiator shield (seen under the front valance) is very apparent on Katie,  as if the body is sitting high on the chassis.  Even with bumpers on, the number plate doesn't drop below the valance enough to disguise that.  But as I cannot change the body mounting's height - then that's something we'll just have to live with.    

Pete

 

 

 

Mine being a non IRS car does sit higher at the rear but I think the stance is fine and yes youve always been able to see the rad shield especially without bumpers as they take your eye away from it. I have refitted the bumpers to mine now and it does look different.

Stuart.

 

[Z320]

Pete,

for sure you own some Triumph books.

Look there for historic TR photos made by Triumph.

Then you will see.

Marco  

[PaulAnderson]

Here's a photographic profile of my TR4A as a comparison of stance.  

The springs were fitted over 20 years ago when the car was first restored.  The statement I made in my insurance declaration records:

'The car has been fitted with the uprated suspension modifications suggested in the Moss TriumphTune catalogue. This was largely on the basis that the original springs are soft, particularly the rear suspension.  Front springs are TT4001 and rear springs re TT4212, both to retain standard height.'

Interestingly, an old Moss  catalogue I've just checked says that the TT4001 is 'Uprated, slightly lowered 6.70" fitted height and 390 Lbs rated.  It records the standard front spring as being 6.75" fitted height and 312 Lbs rating.

The catalogue also says:

The rear end of the IRS TR4A was notoriously weak. Our standard spring (GSV1001 (standard 9.00" ride height 354 Lbs) is in fact a TR6 spring
specification which is slightly uprated (TR4A standard is 280lbs) while GSV1001 is 354lbs, really the minimum strength to use on TR4A’s to avoid the sagging rear end look. We sell hundreds of TT4212 which is a nice compromise between ride and handling, it’s rated at 390lbs, which should not cause any passenger discomfort. We supply a whole range of uprated suspension components in the restoration section

 The TT4212 rear springs are recorded in a table as being Uprated (standard ride height) 8.85" ride height and 390 Lbs.  There seems to be a bit of conflict there between what is a standard ride height spring. 

 

Paul

 

Edited January 31, 2023 by PaulAnderson

[Nigel C]

that looks well balanced 

[Bfg]

Having changed the road-spring rates on Katie,  I think probably back to standard TR4A spec,  as opposed to TR6 rated springs, and driven the car a hundred miles or so to settle those - I next wanted to check the tracking and cambers . . .

^ nine old night storage heater bricks weighed in on my bathroom scales at ~68 kg (150lb) x 2 seats ..because I do refer to the workshop manual, before I rolled the car back into my getting rather restricted workspace.

^ Using the cord around the wheels (shimmed out on each tyre to accommodate difference in front & rear track widths) I first checked the car's present tracking. The front axle was fine, and the back was close but for the rear left having 0.29deg positive rather than toe-in.  I don't think I'd notice less than 1/3rd of a degree crabbing sideways, but as that wheel also has just -0.35 degree of camber, and it should be -1 +/- 0.5 degree on the IRS TR4A - then I'll swap out one of the arm-to-chassis-brackets (one notch difference probably)  and at the same time slip in a shim to correct the tracking.

As you can see from the above photo I checked the wheel cambers against a spirit-level (..distance from the wheel rim top and bottom to that vertical datum).

I'm glad to see that the car is sitting evenly now side to side.

^ I drew these out in AutoCAD, to scale, so that I can see what is what and to measure the angles accurately. 

^ Today I added to that with a rough sketch of the front suspension wishbones. Several dimensions are not given in the workshop manual so I've estimated them, but still it ought to be close enough for my needs.  I need to adjust the LHS front-wheel camber, which presently measured at +0.94 degrees, whereas according to the workshop manual it should be 0 +/- 0.5 degrees.  Personally I prefer just a tad negative camber. Katie's  front-right wheel measured at -0.22 degrees ..which is what I'd like on the LHS. 

On the RHS is of drawing above shows the end view (in this case of the LHS so as if viewed directly from behind). Behind the circle representing the lower fulcrum bush, now mounted into a two stud bracket, I've added three shims (5mm) behind each of those bottom brackets. This according to the drawing swings the upright and hub, and therefore the wheel, out by 1.29 degrees. Given that the car presently has +0.94 then -1.29 degrees ought to give me -0.35 degrees.  And that's pretty darned close to what I want. 

 

But. . . because the rear of this chassis' fulcrum mounts has been plated over (..so I suspect the suspension's castor is out as well) - I'm presently just fitting the three shims behind the front bracket.

Btw the drawing on the left (above) is my plan of the lower wishbones, with three shims behind just the forward lower-fulcrum-bracket.  This both swings the lower wishbones backwards - which shorten the wheelbase on this side, by 5mm, and at the same time lessens this side's steering castor angle. It also advises that I'll need to wind-out the track-rod-end by 2.5mm to correct the steering's tracking.  . .

 

 

^ If logic is anything to go by then by fitting the shims behind just the one bracket (above the shim can just be seen as it was being fitted ..just under under the steering rack) - then instead of those making 1.29 degrees difference (to negative) it ought to make just half that difference.  1.29 / 2 = 0.645 degrees.  This side's camber measured at 0.94 degrees positive, so if my calculations are correct - then I'll end up with +0.295 degrees.  It's not really what I want but (because of the slapped on plate repair) the studs are too short to also fit 5mm of shims behind the rearmost fulcrum bracket. 

I'll just have to try it and see. Hopefully I've miscalculated or miss measured something ..and it will all be fine in the daylight   If not, then it will still be within design tolerance ..just not as right as I'd like it.

Pete

- - -  

for reference  should anyone want to know about what difference these shims make to camber angles on the TR4a (TR250, TR5 and 6 are probably the same) ...

According to what I've drawn.. one new / probably standard shim (1/16" / 1.67mm thick) behind each lower fulcrum - chassis bracket approximates to 0.43 degrees additional negative camber.  Two shims double that, so ~ 0.86 degrees.  Three shims ~ 1.29.  And if you fit three shims behind one of the brackets and two shims behind the other - then I guess you should achieve very close to 1 degree change in camber (to negative).

Edited February 11, 2023 by Bfg

[stuart]

Be careful fitting shims to just one bracket and not the other as you will introduce an amount of binding into the bushes.

Stuart.

[Bfg]

4 hours ago, stuart said:

Be careful fitting shims to just one bracket and not the other as you will introduce an amount of binding into the bushes.

Stuart.

Thanks Stuart. 

By welding a repair plate onto the outside face of just one, the rear, of this chassis' wishbone's lower fulcrum mounts (rather than replacing it for a new one ..as you previously suggested) - the bodgers had introduced the fulcrum axis misalignment / potential binding in the bushes.  My adding shims under just the front bracket, only on this side, aims corrects this. Otherwise your advice is correct to most cars.

Pete 

[Bfg]

I hope all those selling and equally those shopping at Stoneleigh had a great day of it.  I didn't go but instead went across to Sutton Hoo, which for those who don't know is the burial ground of an Anglo-Saxon king, along with his long ship and precious artifacts which he would undoubtedly need in the afterlife.

^ The weather was dry and still aired, but dull and with 10/10th cloud cover all day. Katie's  steering seemed to be tracking much better around Suffolk's B-roads subsequent to the shimmed suspension adjustments I made to her front left corner.

Sutton Hoo is strange for a museum insomuch as the exhibits are mostly reproductions of those now in the hands of the British museum.  Many years ago I visited the Viking Ship museum in Oslo, which houses (I think 3 ?) magnificent longboats (..well the original timbers and most of the frames supported into their correct shape) which you can walk around to admire their incredible lines and stature.  I've also visited the museum on the shore of Galilee, which houses the timber remains of a first century A.D. fishing boat (..colloquially known as the Jesus boat), so coming here - I guess I'd hoped to see something of the original ship &/or the archeological diggings, perhaps showing its imprint in the soil.  Alas not . . .

   

The notice explains and illustrates the position of the burial mounds, which actually doesn't make much sense as the large one illustrated on the plan (partly over the track to the right) is "the Great ship Burial - the King's mound burial chamber is inside the ship" but then the large mound (2) at the bottom of the site plan is "Ship Burial - burial chamber underneath the ship. Robbed about 1600 and 1860. Excavated in 1938 and 1988. Reconstructed to original size" (my photo right).  Seven of the 18 mounds are "Un-excavated, Probably robbed", another was "thought to be a burial mound, but this is now in doubt"

Each have been robbed, probably robbed, or unsuccessfully robbed.  And most are little more than undulations in the coarse grass, where . . .

^ odd looking sheep graze freely over the burial grounds. 

^ There's a pretty impressive sculpture in the car-park depicting (at many times the scale) the buried king's helmet.  And also a tubular-steel full-sized depiction of a long-ship's frames. Unfortunately they are broadly spaced and so don't really give a clear impression of the ship's lines or its stature. There was no model of the ship in the museum, nor a model of the burial site Disappointingly then, this museum is not even a dim shadow of those in Norway and Israel.  For the National-Trust's gate price I had expected more.

Still, even on a dull February day - it is a very pleasant park to walk around. . .

   

   

 

^ easy to walk paths in pleasant countryside. I liked their stylish idea of a garden seat, and the views over the Deben to Woodbridge.

I took the long way around to get there, and with so very little traffic it was a pleasant open-aired drive.  An hour or so's walk was a little Sunday afternoon exercise and I bought what I hope will be an interesting book 'the Red Prince - John of Gaunt' by Helen Carr, in the museum's second-hand book store.  

All in all a pleasant afternoon to drive out and have a walk around. 

Bidding you a good evening,

Pete.

 

   

[Mk2 Chopper]

I was planning to go and see this place. There was a recent film about the 1938/9 excavation, which it revealed the ship was just an impression left in the soil, still amazing to see, but covered up again into the mound and of course the artifacts that are housed at the British museum. 

So I didn't know what I would actually get to see, so I'm glad you got round to going here. I may well go elsewhere now.

Gareth

 

[john.r.davies]

Gareth, 

Have you seen "Digging for Britain" on BBC2?    That programme shows some of the many digs going on at present.   Many will show you around the dig, let you see some of the finds and explain their significance.  EG and from last night's prog, https://aucklandproject.org/news/archaeology-shines-new-light-on-medieval-lives/

JOhn

[Mk2 Chopper]

No I don't believe I have John, I'll check them out, thanks. 

Gareth

[PaulAnderson]

I believe that film was called The Dig with details as listed on IMDB.  Quite a good film and probably available on demand.  Sutton Hoo has been on several TV programmes due to its historical significance.  I’ve seen the original treasures in the British Museum in London and they’re amazing.

Paul

 

ps, I think that sheep is a herdwick and they’re not odd.  They’re descended from the Vikings and common in the Lake District. See photos on Flickr  oh, and they taste lovely.

Edited February 13, 2023 by PaulAnderson

[Bfg]

5 hours ago, Mk2 Chopper said:

I was planning to go and see this place. There was a recent film about the 1938/9 excavation, which it revealed the ship was just an impression left in the soil, still amazing to see, but covered up again into the mound and of course the artifacts that are housed at the British museum. 

So I didn't know what I would actually get to see, so I'm glad you got round to going here. I may well go elsewhere now.

Gareth

It saddens me to give a poor review of places I've been to (..or services I use) but this is one of those cases where the entry cost ..presently £15 / adult, unless you're a member of the National Trust..  is not (imo) balanced with good value.  There are plenty of lovely places to walk around Suffolk that don't cost anything (..sometime perhaps a modest parking fee). 

However, to be fair - I have to confess that I went into the site's museum building, into the shop and cafe, into the building which housed the used book store, and I walked around the park for over an hour, but I didn't know to go into Tranmer House, former home of Edith Pretty, built in 1910.  I'm not particularly interest in country houses and didn't know who Edith Pretty was (Wiki says she was Yorkshire born, landowner, benefactor, magistrate). 

Apparently she owned the land ..the Sutton Hoo ship burial was discovered on, and hired Basil Brown (a local excavator and amateur archeologist) to find out what, if anything, lay beneath the mounds on her property.  I've subsequently read that her former home 'displays exploring the archaeological work that has taken place at Sutton Hoo'.  How interesting that display is I cannot say

Current Archeology did a review in 2019 < here > of the site and their visit to Sutton Hoo.  I didn't see any photograph or detailed model of the ship or the burial in the museum but perhaps there were some in Tanmer house.  The heritage of this site was corrupted by pillagers and then dug by "local excavator and amateur archeologist "  The article I linked to further says the "gardener who (together with the gamekeeper, William Spooner) had been enlisted to help with the digging". 

And then "With the outbreak of the Second World War, digging had to cease. The ship burial was covered with a protective layer of bracken, and its grave goods were spirited away to London where they waited out the war deep in the (now-defunct) Aldwych tube station. Even so, this did not prevent the site from being damaged by military action – by our own forces. Throughout the war, Sutton Hoo was used as a military training ground, with the mounds brought into service to practice tank manoeuvres : to this day, the site still bears the scars of their tracks, and of anti-glider trenches. Excavations would not return to Sutton Hoo until 1965." 

As I read it ; the tanks used the mounds and the archeologist's trench and ship remains, covered with bracken, to practice tank maneuvers.

I'm left with the impression that Sutton Hoo was a travesty of greed (repeated grave robbers) and then egocentric archeologists (amateurish and still never completed), and that the military were total plonkers (there are thousands of others sites that might otherwise have been used for training).  What really is the point of a country fighting a world war when we don't try to preserve the history and the culture of its people ? 

Now Sutton Hoo is a just a park, albeit with a poignant recent history.  

but it could have been so much more . . . .

  

^ Sutton Hoo before it was trampled over by British tanks and later filled in again - versus - The Viking Ship Museum, Oslo.

- - -

 

If and when you do come up this way Gareth, do drop me a line.. The kettle's on.  

and < here's >  a link to a local town's website listing local attractions.

Pete

Edited February 13, 2023 by Bfg

[Mk2 Chopper]

1 hour ago, Bfg said:

If and when you do come up this way Gareth, do drop me a line.. The kettle's on.  

and < here's >  a link to a local town's website listing local attractions.

Pete

Thanks for the offer Pete, very nice. 

Looks to be a fair few things in just that local area too.

Will let you know...

Cheers

Gareth

[Ralph Whitaker]

It looks to my untrained eye that if you want to see what the ship at Sutton Hoo looked like, take a look at the Viking ship museum, they seem very similar in shape to me.

Ralph

[Bfg]

Carrying on with my adjustments of the front-left suspension's castor and camber, c. 9th February, the measured results were not quite as much as my sketched geometry had implied they would be.  I suspect that when making the drawing - I must have pick & mixed TR4 versus TR4A wishbone and chassis mount dimensions from the workshop manual.  In short I got it wrong and had to re-do the work again ..in my own time and without pay . . .

 

^ the LHS of this drawing shows my revised sketch (for TR4A and later models) versus the previous sketch (RHS of this drawing) which is much closer in configuration to the TR4.  I hadn't realised the front suspension changed so much between models, but perhaps a clue was in their spec'ing a 2-deg positive camber angle (static laden) for the TR4, versus the TR4A being 0-degrees camber. 

The most notable differences between the above drawings is where the bottom outer-fulcrum pin attaches to the upright (steering trunnion) and the relative position of the ball joint of the top wishbones (which I'd roughly guessed at before but later found clearer information to work from).  With the suspension's  unequal wishbone lengths and different chassis mounts - the swing in geometry is mostly seen the angle of the lower wishbones, and of course that different geometry alters the results of adjustments made.

Bottom line, is that (according to the earlier geometry sketch) - fitting x3 (5mm) of shim (..behind just the front) lower fulcrum bracket should have altered the camber by -1.29° / 2 = -0.645°  but (when measured) it adjusted by just 0.43°.   The camber was (without the shims) +0.94° and with those shims it measured at +0.51°. 

As it was Katie's  LHS wheel leaned out and the RHS wheel camber leaned in, albeit each (now) by just a tad.  The RHS measured as -0.22° which is fine. The W.S.Manual specifies  0° +/- 0.5°  so the result was very close to tolerance, but I'd prefer both wheels to each have a slightly negative camber of -0.5° to -1°.   This preference is founded on what Stuart and Marco have said, and again what seems right to me ..insomuch as I'd prefer to lessen wheel tuck-under in cornering. 

The car's overall stance is not helped by the rear wheel's cambers.. which on this car measured at -0.15° on the rear LHS and -1.31° on the RHS.  so again the LHS wheel is very close to vertical whereas the RHS rear wheel leans in.

For the IRS TR4A, for the rear wheels camber ; the book specifies  -1 +/- 0.5°.   So again Katie's  rear RHS is correct and the LHS would benefit from another degree of negative camber.  As set up (both front and rear wheel cambers) the car ought to handle slightly better around left rather than right handed corners    ..not that I, or any other average driver, might actually notice the difference.  But, perhaps like with the brakes ~ being slightly out of adjustment is barely noticeable in normal use ..but in an emergency situation, that little bit of fine adjustment may make all the difference.  Aside from that ..as I'm a retired engineer I'm 'having fun' with my hobby.

So.., and from what (I thought) I'd read from Marco, reversing the top fulcrum pin would take that inwards by 2.5mm. . . 

  

^ removing the upper wishbones was done without taking the spring and damper off.  As the lower wishbone is sprung against the chassis, the top wishbones only provide the location for the top of the upright.. ie., the upright and steering trunnion., so with the chassis on blocks, the trolley jack was used to support the hub and raise the wishbone arms to level.   The two top arms have a different offset ..which facilitates the steering's castor angle, and so when the upper fulcrum pin is reversed (to alter their offset relative to the mounting bolt holes) the arms also have to be swapped around.      

^^ I had issues with the screw threads of the upper fulcrum pin into the chassis when I had the suspension off before. I cleaned out the threads with a tap, and it did go back together again - but was not happy when the thread in one of the rear fastenings bound up tight.  While the top wishbone was off again, I chose to correct that previously crossed and now part stripped thread by tapping the hole out for the next size of bolt.  In this case I succumbed to using an M8 .  That is the very next size up and was used because it avoids needing to enlarge the hole through the fulcrum pin's casting.  I've deliberately used an Allen headed set screw in that hole to differentiate it, and I've marked the chassis next to it with 'M8' so it's obviously different to whomever next takes this suspension apart. 

Job done.  However according to my revised sketch and the 2.5mm change in offset of those pins - this should have altered that front-left camber from +0.94° to -0.03°.   Whereas doing so resulted in the camber to change to -1.31° ..way too much !   Either the top fulcrum pin's offset was different to what I'd understood from Marco (who perhaps meant 2.5mm from a centre between the bolt holes),   &/or my drawing's geometry,  &/or my measurements were in error.  Things were now becoming a little more frustrating.  

Back to the drawing board . . .

  

^ from the W.S.manual, the axis of the upright (vertical link) ie. between the bottom steering trunnion and the top ball joint, is notated to be 9° from the vertical.  You'll note that the top wishbones are shown horizontal. In engineering draughting, unless otherwise stated, it is usual practice to draw such assemblies in their designed working / static load condition.. and this situation is confirmed to be the case by the hub's axis also being shown horizontal ..which in turn corresponds to the wheel camber's specification of 0 +/- 0.5°.

But that drawing's horizontal top wishbone does not match what i see on the car, so revising my ACAD drawing again - I've tried to 'reverse engineer' the overall geometry to reflect the 0.94° positive camber measured at this wheel.  As the angle between the wheel (the hub spindle) and the upright us fixed - I started by swinging the wheel and its hub to the measured wheel camber. This swung the upright's axis to 8.06° from the vertical. 

And then the only way the rest of the given dimensions (ie., the wishbone lengths and the positions of the mounts on the chassis) link together was to drop the wheel (which is the same as raising the suspension's ride height).  The drawing reveals the ride height is much higher than designed, and as a consequence the top wishbone swings down from the horizontal to about 11° , and the bottom wishbone swings down by 7.4° (..because of their different length).   Naturally this ride height is seen when looking at the car, and yes.. the car has been high since the chassis change and although it's now a little lower than it was, there's (vertically) still 3-1/2" (88mm) between the top of the tyre and the underside of the lip of the wheel-arch. 

The difference in geometry between my first and last drawing permutations is obvious, and of course any changes made by shimming, &/or reversing the upper fulcrum pin, would show different results from each.  I've now taken one of the three shims out from under the bottom wishbone's inner fulcrum bracket. Now there's x2 under that polybush bracket, and non under the rear wishbone bracket ..which instead has a repair / reinforcing plate on it. 

I've not rechecked the car yet with the 150lb (68kg) load in each seat, but I have roughly reset the toe-in and then driven the car another 100 miles or so ..to settle things, and today checked this front wheel's camber (unloaded).  It presently reads -0.44°  ..which I am happy with.

NOTE : Unequal wishbone lengths - when cornering and when the suspension is compressed ...

With Katie's  suspension sitting too high at the front ; the upper wishbones are not horizontal, so when the suspension is compressed the upper ball joint swings through an arc outwards by 5.24mm, until it is horizontal with the inner fulcrum pins. The bottom wishbones raised by the same distance as the suspension is compressed, and the outer fulcrum pins swing through their arc outwards by 9.94mm. In terms of effecting camber ; the sum of these changes are (9.94 - 5.24mm =) 4.5mm ..This would similar to 3 more shims under the bottom wishbone brackets) to alter the camber angle towards negative.

However, if the ride height were correct (ie. lower ) ..so that the upper wishbone started off horizontal (as shown in the W.S.manual) then the upper ball joint would swing inwards by 2.97mm, for the same amount of vertical travel cited above.  The bottom wishbone's outer fulcrum pin (still not horizontal with the inner polybushes) would swing outwards by  4.38mm.. The sum of change is (2.97mm + 4.38 =) 7.35mm to alter the camber angle towards negative even more. This when cornering hard would angle the wheel and tyre out at the bottom

It'll do for the time being ..but I really ought to try again to lower Katie's  front suspension ride height.   That said, checking the effect of lowering the front of the car by 20mm, and it seems that it would be much the same as if I fitted just one extra shim behind the bottom wishbone brackets.  so it's really not worth the effort.

- - -

As is said above "The car's overall stance is not helped by the rear wheel's cambers.. which on this car measured at -0.15° on the rear LHS and -1.31° on the RHS.  so again the LHS wheel is very close to vertical whereas the RHS rear wheel leans in. "

This wheel also had a slight toe-out, by 0.29°. The resolution of each was to swap out the outer bracket and remove one of the two shims between it and the chassis . . .  

 

^ This bracket was also swapped out without removing the spring. With the hub supported on the trolley jack and the front of the trailing arm resting on blocks, the bolt pulled out smoothly to the inside, and with that out, and the arm pulled back a bit to get the spanner onto the top through-chassis bolts, those were undone and the bracket could then swing downwards and be pulled off the polybush. NB. The inside bracket's chassis-through-bolts were loosened just a little to give a little free movement of the arm, so that the bracket could more easily be pulled out and be replaced. 

^ Referencing the chart I'd used before - I swapped this outer bracket from 2D (two notches facing down) to 1U (one notch up). This raised that outer polybush by 1/8" ..to tilt the trailing arm and the hub, and therefore the wheel inwards at top.  According to the chart (bottom LH corner) this ought to alter the wheel camber from -1.02° to -1.63°   ..or 0.61°.  And as it was -0.15° then that should result in the wheel camber now being -0.76° ..which is within the specified tolerance of -1 +/-0.5°.   Again I have not yet checked this with the car loaded, but am confident that it's now better than it was.

Removing the shim corrected this wheel's toe-out tracking. 

Job done.  

The front of the car is still sitting an inch higher than I would like.. but I think the body is high at the front on the chassis by half an inch, as the chassis has just 1/2" greater ground-clearance than it should have.  The softer (standard) front springs can be noticed though..  as being better balanced with the standard rear springs.  

I felt beforehand that the car's rear quarter would squat down around corners whereas the front did not, and that felt uneasy / a little unpredictable.  Now the front and rear spring rates feel much better matched with less load on the steering and the tail end feeling less squidgy.  Quite probably the car rolls a tad more but that's much better than the tail end going down and feeling as its rolling under.  I'll need to wait until my sprained wrist has healed before I push my luck around corners and find myself drifting, but Katie  already feels safer.  For me, the effort has been worth it.  These are just my impressions of course and a better driver or another person following might see how things might still be improved.

Pete 

 

Edited March 3, 2023 by Bfg

[Z320]

Pete,

I measured the shaft 2.25 mm out of center between the bolts (20.0 mm VS 24.5 mm)

Turn the falcrum pin 180 deg. changes the offset 4.5 mm, not only 2.50 mm.

Ciao, Marco 

[Lebro]

 "The two top arms have a different offset ..which facilitates the steering's castor angle, and so when the upper fulcrum pin is reversed (to alter their offset relative to the mounting bolt holes) the arms also have to be swapped around".    

Pete.

I don't understand your comment "the arms have to be swapped round"  If you swap upper wishbones front to back you would be unable to fit the vertical link as the top would be behind the top ball joint by some distance ?

Bob

[Bfg]

30 minutes ago, Lebro said:

 "The two top arms have a different offset ..which facilitates the steering's castor angle, and so when the upper fulcrum pin is reversed (to alter their offset relative to the mounting bolt holes) the arms also have to be swapped around".    

Pete.

I don't understand your comment "the arms have to be swapped round"  If you swap upper wishbones front to back you would be unable to fit the vertical link as the top would be behind the top ball joint by some distance ?

Bob

after swapping the wishbones over - the fulcrum pin casting together with wishbones are turned around 180-deg as an assembly ..this facilitate offsetting the pins inwards ..and the gap between wishbones, for the ball-joint, comes back into the same place, aside from it being inboard by the 4.5mm Marco writes of. 

Pete

[Bfg]

9 hours ago, Z320 said:

Pete,

I measured the shaft 2.25 mm out of center between the bolts (20.0 mm VS 24.5 mm)

Turn the falcrum pin 180 deg. changes the offset 4.5 mm, not only 2.50 mm.

Ciao, Marco 

Thank you Marco. That is useful information

Being an English manufacturer, using 'imperial' measurements of 1/32" units, the dimension might perhaps have been 3/32" measured, which when turned around 180-deg would be  3/16" (4.76mm) change ?     ...and 3x 1/16" would be the equivalent of 3x shims at the bottom fulcrum, which you have not fitted.

Pete

 

 

Edited March 3, 2023 by Bfg